Question

State why concentrated sulphuric acid is not used for drying ammonia gas.

Answer 1

Drying of ammonia gas:

• No, we can not use concentrated Sulphuric acid to dry the ammonia gas because ammonia is basic in nature and can react with concentrated Sulphuric acid, and then it will form ammonium sulphate.
• The balanced chemical reaction can be represented as:

$\underset{\mathrm{Ammonia}}{2{\mathrm{NH}}_3\left(\mathrm{g}\right)}+\underset{\mathrm{Sulphuric}\mathrm{acid}}{{\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)}\to \underset{\mathrm{Ammonium}\mathrm{sulphate}}{{\left({\mathrm{NH}}_4\right)}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)}$

Therefore, ammonia gas is dried by passing through a dry tower containing lumps of calcium oxide(quick lime)

Therefore, concentrated sulphuric acid is not used for drying ammonia gas.